Fault-tolerant method for demodulating 5G or 6G messages

Abstract

With rapid increases in the number and spatial density of wireless messages as 5G and 6G are rolled out, it is essential that improved methods for fault-tolerant demodulation and error mitigation be developed. Disclosed herein are methods for receiving a message concatenated with a demodulation reference, determining the predetermined modulation levels of a modulation scheme, and demodulating the message by measuring the amplitude mad/or phase modulation values of each message element. The measured modulation values are then compared with the predetermined modulation levels of the modulation scheme to demodulate the message. Importantly, the message can be demodulated by determining an amplitude and phase of the raw signal for each message element, or by separating the raw signal into two orthogonal “branches” and determining the amplitudes of the two branches. By demodulating the message both ways, message faults may be identified and mitigated, according to some embodiments.

The invention claimed is: 
     
       1. A method for a wireless receiver to demodulate a message, the method comprising:
 a) receiving a raw signal comprising the message; 
 b) downshifting the raw signal from a first frequency to a lower second frequency; 
 c) separating, from the raw signal, one or more message elements, each message element comprising a single modulated resource element of the message; 
 d) for each message element, measuring one or more measured modulation values, each measured modulation value comprising a measured amplitude value or a measured phase value; 
 e) comparing each measured modulation value to one or more predetermined modulation levels of a modulation scheme; and 
 f) selecting which of the predetermined modulation levels is closest to the measured modulation value. 
 
     
     
       2. The method of  claim 1 , wherein the message is received according to 5G or 6G technology. 
     
     
       3. The method of  claim 1 , wherein:
 a) the modulation scheme comprises phase modulation at constant amplitude; 
 b) the phase modulation includes at least two predetermined phase levels; and 
 c) the measured modulation values comprise a measured phase value of each message element. 
 
     
     
       4. The method of  claim 1 , wherein:
 a) the modulation scheme comprises both amplitude modulation and phase modulation; and 
 b) for each message element, the measured modulation parameters comprise a measured amplitude value of the message element and a measured phase value of the message element. 
 
     
     
       5. The method of  claim 1 , wherein:
 a) each message element comprises a first branch signal and a second branch signal, the first and second branch signals separated by 90 degrees of phase; 
 b) the modulation scheme comprises amplitude modulation of the first branch signal and amplitude modulation of the second branch signal; and 
 c) for each message element, the measured modulation values comprise a first measured amplitude value of the first branch signal and a second measured amplitude value of the second branch signal. 
 
     
     
       6. The method of  claim 1 , further comprising:
 a) receiving a demodulation reference modulated according to the modulation scheme; 
 b) separating the demodulation reference into one or more reference elements, each reference element of the demodulation reference comprising a single modulated resource element of the demodulation reference; and 
 c) for each reference element of the demodulation reference, determining one or more of the predetermined modulation levels of the modulation scheme. 
 
     
     
       7. The method of  claim 1 , wherein:
 a) a resource grid comprises resource elements, each resource element comprising a single symbol-time in time and a single subcarrier in frequency; 
 b) the message elements occupy multiple symbol-times at a single subcarrier; 
 c) a demodulation reference is concatenated with the message, either preceding the message in time or following the message in time; and 
 d) the demodulation reference indicates one or more of the predetermined modulation levels of the modulation scheme. 
 
     
     
       8. The method of  claim 1 , wherein:
 a) a resource grid comprises resource elements, each resource element comprising a single symbol-time in time and a single subcarrier in frequency; 
 b) the message elements occupy multiple subcarriers at a single symbol-time; 
 c) a demodulation reference is concatenated with the message, either preceding the message in frequency or following the message in frequency; and 
 d) the demodulation reference indicates one or more of the predetermined modulation levels of the modulation scheme. 
 
     
     
       9. The method of  claim 1 , wherein the separating one or more message elements comprises:
 a) digitizing the raw signal, after the downshifting, by repeatedly measuring a signal voltage and recording, in a memory, the voltage measurements; and 
 b) for each message element, determining a particular frequency corresponding to the subcarrier of the message element, and determining, from the voltage measurements, a message element signal at the particular frequency. 
 
     
     
       10. The method of  claim 1 , further comprising:
 a) receiving a first demodulation reference preceding the message in time or in frequency; 
 b) receiving a second demodulation reference following the message in time or in frequency; 
 c) determining a first modulation value according to the first demodulation reference, and determining a second modulation value according to the second demodulation reference; and 
 d) determining a modulation level of the modulation scheme by averaging the first and second modulation values. 
 
     
     
       11. A wireless receiver configured to:
 a) receive a demodulation reference modulated according to a modulation scheme; 
 b) determine, based on the demodulation reference, at least two predetermined modulation levels of the modulation scheme, each of the predetermined modulation levels comprising an amplitude level or a phase level; 
 c) calculate, based on the at least two predetermined modulation levels, at least one additional predetermined modulation level of the modulation scheme; 
 d) receive a message comprising message elements; 
 e) for each message element, determine one or more measured modulation values; and 
 f) for each measured demodulation value, determine which of the predetermined modulation levels of the modulation scheme is closest to the modulation value. 
 
     
     
       12. The wireless receiver of  claim 11 , further configured to, for each message element:
 a) determine a raw signal comprising a received signal at a particular frequency corresponding to a subcarrier of the message element; 
 b) determine a raw signal amplitude and a raw signal phase based on the raw signal of the message element; 
 c) determine which of the predetermined modulation levels of the modulation scheme is closest to the raw signal amplitude and the raw signal phase; 
 d) determine an I-branch signal and a Q-branch signal orthogonal to the I-branch signal; 
 e) determine an I-branch amplitude based on the I-branch signal and a Q-branch amplitude based on the Q-branch signal; and 
 f) determine which of the predetermined modulation levels is closest to the I-branch amplitude and which of the predetermined modulation levels is closest to the Q-branch amplitude. 
 
     
     
       13. The wireless receiver of  claim 12 , further configured to:
 a) determine whether the message, when demodulated according to the raw signal amplitude values and the raw signal phase values of the message elements, agrees with an error-detection code associated with the message; 
 b) determine whether the message, when demodulated according to the I-branch amplitudes and the Q-branch amplitudes, agrees with the error-detection code; 
 c) transmit a positive acknowledgement message if the message agrees with the error-detection code, when demodulated according to the raw signal amplitudes and phases, or when demodulated according to the I-branch and Q-branch signals; and 
 d) transmit a negative acknowledgement message if the message fails to agree with the error-detection code, when demodulated according to the raw signal amplitudes and phases, and when demodulated according to the I- and Q-branch signals. 
 
     
     
       14. The wireless receiver of  claim 13 , further configured to:
 a) for each message element, determine a raw signal amplitude deviation comprising a difference between the raw signal amplitude and the closest predetermined modulation level, a raw signal phase deviation comprising a difference between the raw signal phase and the closest predetermined modulation level, an I-branch amplitude deviation comprising a difference between the I-branch amplitude and the closest predetermined modulation level, and a Q-branch amplitude deviation comprising a difference between the Q-branch amplitude and the closest predetermined modulation level; 
 b) for each message element, determine, according to the raw signal amplitude deviation, the raw signal phase deviation, the I-branch amplitude deviation, and the Q-branch amplitude deviation, a modulation quality of the message element; and 
 c) determine which message element has a lowest modulation quality. 
 
     
     
       15. The wireless receiver of  claim 14 , further configured to:
 a) for each message element, determine a signal-to-noise ratio or a signal-to-interference-and-noise ratio (collectively, “SNR”); and 
 b) for each message element, determine the modulation quality of the message element based at least in part on the SNR of the message element. 
 
     
     
       16. Non-transitory computer-readable media containing instructions that when implemented in a computing environment cause a method to be performed, the method comprising:
 a) receiving a message comprising message elements, each message element comprising a resource element of a resource grid, the message elements occupying a first plurality of subcarriers at a single symbol-time of the resource grid; 
 b) digitizing the message by repeatedly measuring a voltage representing a sum of individual signals, each individual signal representing one of the message elements, respectively; 
 c) then separately determining, from the digitizing, each individual signal of the sum of individual signals; and 
 d) for each individual signal, of the sum of individual signals, measuring at least one measured modulation value comprising an amplitude value or a phase value, and determining which predetermined modulation level, of a modulation scheme, is closest to the measured modulation value. 
 
     
     
       17. The media of  claim 16 , the method further comprising:
 a) receiving a demodulation reference during the single symbol-time, on a second plurality of subcarriers different from the first plurality of subcarriers; 
 b) determining, according to the demodulation reference, a maximum positive amplitude and a maximum negative amplitude; and 
 c) determining, based on the maximum positive amplitude and the maximum negative amplitude, all of the predetermined modulation levels of the modulation scheme. 
 
     
     
       18. The media of  claim 16 , wherein the digitizing the message further comprises downshifting the message by converting a frequency of the message to a lower frequency. 
     
     
       19. The media of  claim 16 , wherein the separately determining each individual signal of the sum of individual signals comprises:
 a) for each subcarrier, of the first plurality of subcarriers, extracting from the sum of individual signals a particular individual signal having a frequency of the subcarrier. 
 
     
     
       20. The media of  claim 16 , wherein the measuring at least one measured modulation value comprises at least one of:
 a) measuring an amplitude of the individual signal; 
 b) measuring a phase of the individual signal; and 
 c) separating the individual signal into an I-branch signal and a Q-branch signal orthogonal to the I-branch signal, and measuring both an I-branch amplitude of the I-branch signals and a Q-branch amplitude of the Q-branch signal.